Preparation And Properties Of Hybrid Polymer Of Waterborne Alkyd/Acrylic/Silicone

This paper used acrylic acid to modify the waterborne alkyd resin,to overcome its shortcomings of slow drying speed and low coating hardness.Further,siloxanes and Ethyl orthosilicate were introduced into the system to enhance its overall performance,such as water resistance and heat stability.In this paper,linseed oil and pentaerythritol were used as raw materials of alcoholysis at 220? ~ 230?,with 0.05wt% LiOH as catalyst.Ethanol Tolerance of the product was more than 4,indicated the higher ratio of newly formed diols,which was favorable for the esterification reaction.The product of alcoholysis and phthalic anhydride(PA)reacted for 3 hours at 180? and were heated to 230°C by 20°C /h,by solvent method.It was found that the dosage of dimethylolpropionic acid(DMPA)had a significant effect on water solubility and water resistance.When the dosage of DMPA was more than 13.2wt%,the product had good water solubility,however,when DMPA was used more than 18.2wt%,the water resistance of the resin decreased.Oil length(OL)and alcohol excess(R)mainly affected the hardness and water resistance of the resin.When the OL was 45 ~ 55wt% and R was 10~ 17%(n/n),the hardness of the coating was HB,and its water resistance test was less 3d.The emulsion of the waterborne alkyd resin was transparent and its storage time last more than 6 months,when the product was neutralized to 120%(n/n)with ethylene glycol butyl ether as cosolvent and triethylamine as neutralizer.Styrene(ST),hydroxyethyl acrylate(HEA)and methacrylic acid were used to modify the waterborne alkyd resin,to improve its drying performance and hardness.The reaction was so difficult that the temperature was set at 120?,with 11wt% of benzoyl peroxide(BPO)as catalyst,last for 5h,to make system smooth and the product stable.When the amount of acrylic acid is 20% by weight and ST: HEA is 1:1,the modified polymer had good water solubility with storage longer than 6 months.When the amount of acrylic acid was 20wt% and ST:HEA was 1:1(wt).The drying performance and hardness of modified resin was effectively enhanced,given that the coating was dry within 3h and its hardness reached H.Methyl triethoxysilane(MTES)and Tetraethyl orthosilicate(TEOS)were introduced into the system on the basis of acrylic modified alkyd resin to prepare waterborne alkyd/acrylic/silicone.The introduction of silicone made the system excellent water resistance and thermal stability,while hybrid polymer coating tolerated immersion in salt water more than 3d and TGA test showed that the polymer began to decompose until 250 ?.The results showed that the hybrid polymer was stable and its water solubility was good,when the amount of silicone was 11wt%,MTES: TEOS = 3:1,the reaction temperature was 85 ?.